the incidence of NPAFP was directly proportional to doses of oral polio received

This shows that the non-polio AFP rate increases in proportion
to the number of polio vaccines doses received in each area.

it is sad that, even
after meticulous surveillance, this large excess in the incidence
of paralysis was not investigated as a possible signal, nor was
any effort made to try and study the mechanism for this spurt
in non-polio AFP.
These findings point to the need for a critical
appraisal to find the factors contributing to the increase in non-
polio AFP with increase in OPV doses – perhaps looking at the
influence of strain shifts of entero-pathogens induced by the
vaccine given practically once every month.

With polio eradication there was
a huge increase in non-polio AFP, in direct proportion to the
number of doses of the vaccine used. Though all the data was
collected within an excellent surveillance system, the increase
was not investigated openly.